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Rough Cocklebur

Xanthium strumarium

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
For more information please download the BSBI Code of Conduct PDF document.


Plant Profile

Flowering Months:
Asteraceae (Daisy)
Also in this family:
Alpine Blue Sow-thistle, Alpine Cotula, Alpine Fleabane, Alpine Saw-wort, Annual Ragweed, Annual Sunflower, Argentine Fleabane, Autumn Hawkbit, Autumn Oxeye, Beaked Hawksbeard, Beggarticks, Bilbao Fleabane, Black Knapweed, Black-eyed Susan, Blanketflower, Blue Fleabane, Blue Globe-thistle, Bristly Oxtongue, Broad-leaved Cudweed, Broad-leaved Ragwort, Brown Knapweed, Butterbur, Buttonweed, Cabbage Thistle, Canadian Fleabane, Canadian Goldenrod, Carline Thistle, Chalk Knapweed, Chamois Ragwort, Changing Michaelmas Daisy, Chicory, Chinese Mugwort, Chinese Ragwort, Coltsfoot, Common Blue Sow-thistle, Common Cat's-ear, Common Cudweed, Common Daisy, Common Dandelion, Common Fleabane, Common Goldenrod, Common Groundsel, Common Michaelmas Daisy, Common Mugwort, Common Ragwort, Common Wormwood, Coneflower, Confused Michaelmas Daisy, Corn Chamomile, Corn Marigold, Cornflower, Cotton Thistle, Cottonweed, Creeping Thistle, Daisy Bush, Dwarf Cudweed, Dwarf Thistle, Early Goldenrod, Eastern Groundsel, Eastern Leopardsbane, Elecampane, English Hawkweed, Fen Ragwort, Feverfew, Field Fleawort, Field Wormwood, Fox and Cubs, French Tarragon, Gallant Soldier, Garden Lettuce, Giant Butterbur, Glabrous-headed Hawkweed, Glandular Globe-thistle, Glaucous Michaelmas Daisy, Globe Artichoke, Globe-thistle, Goat's Beard, Golden Ragwort, Golden Samphire, Goldilocks Aster, Grass-leaved Goldenrod, Great Lettuce, Greater Burdock, Greater Knapweed, Grey-headed Hawkweed, Guernsey Fleabane, Hairless Blue Sow-thistle, Hairless Leptinella, Hairy Michaelmas Daisy, Harpur Crewe's Leopardsbane, Hawkweed Oxtongue, Heath Cudweed, Heath Groundsel, Hemp Agrimony, Highland Cudweed, Hoary Mugwort, Hoary Ragwort, Hybrid Knapweed, Intermediate Burdock, Irish Fleabane, Jersey Cudweed, Jerusalem Artichoke, Lance-leaved Hawkweed, Lavender-cotton, Leafless Hawksbeard, Least Lettuce, Leopardplant, Leopardsbane, Leptinella, Lesser Burdock, Lesser Hawkbit, Lesser Sunflower, London Bur-marigold, Magellan Ragwort, Marsh Cudweed, Marsh Hawksbeard, Marsh Ragwort, Marsh Sow-thistle, Marsh Thistle, Meadow Thistle, Melancholy Thistle, Mexican Fleabane, Milk Thistle, Mountain Everlasting, Mouse-ear Hawkweed, Musk Thistle, Narrow-leaved Cudweed, Narrow-leaved Hawkweed, Narrow-leaved Michaelmas Daisy, Narrow-leaved Ragwort, New England Hawkweed, New Zealand Holly, Nipplewort, Nodding Bur-marigold, Northern Hawksbeard, Norwegian Mugwort, Oxeye Daisy, Oxford Ragwort, Pearly Everlasting, Perennial Cornflower, Perennial Ragweed, Perennial Sow-thistle, Perennial Sunflower, Pineapple Mayweed, Plantain-leaved Leopardsbane, Ploughman's Spikenard, Plymouth Thistle, Pontic Blue Sow-thistle, Pot Marigold, Prickly Lettuce, Prickly Sow-thistle, Purple Coltsfoot, Rayed Tansy, Red Star Thistle, Red-seeded Dandelion, Red-tipped Cudweed, Robin's Plantain, Roman Chamomile, Rough Hawkbit, Rough Hawksbeard, Russian Lettuce, Safflower, Salsify, Saw-wort, Scented Mayweed, Scentless Mayweed, Sea Aster, Sea Mayweed, Sea Wormwood, Seaside Daisy, Shaggy Mouse-ear Hawkweed, Shaggy Soldier, Shasta Daisy, Shetland Mouse-ear Hawkweed, Shrub Ragwort, Sicilian Chamomile, Silver Ragwort, Slender Mugwort, Slender Thistle, Small Cudweed, Small Fleabane, Smooth Cat's-ear, Smooth Hawksbeard, Smooth Sow-thistle, Sneezeweed, Sneezewort, Spear Thistle, Spotted Cat's-ear, Spotted Hawkweed, Sticky Groundsel, Stinking Chamomile, Stinking Hawksbeard, Tall Fleabane, Tall Mouse-ear Hawkweed, Tansy, Thin-leaved Sunflower, Trifid Bur-marigold, Tuberous Thistle, Tyneside Leopardplant, Viper's Grass, Wall Lettuce, Welsh Groundsel, Welted Thistle, White Butterbur, White Buttons, Willdenow's Leopardsbane, Winter Heliotrope, Wood Burdock, Wood Ragwort, Woody Fleabane, Woolly Thistle, Yarrow, Yellow Chamomile, Yellow Fox and Cubs, Yellow Oxeye, Yellow Star Thistle, Yellow Thistle, York Groundsel
Life Cycle:
Maximum Size:
150 centimetres tall
Fields, riverbanks, roadsides, wasteland, waterside.

Green, no petals
There are many flowers (20+) held closely together in compact globular clusters. The clusters appear in the angles between the stem and the leaves. Reddish-coloured anthers. Insect-pollinated.
The fruit is a dark brown or black seedpod, covered in hooked prickles. The fruits (burs) look similar to those of Burdock. The seeds ripen from August to October.
An annual plant with oval to triangular, long-stalked leaves. The leaves are slightly palmately lobed (3 to 5 lobes). They measure about 6 inches (15cm) long. The surfaces of the leaves have a texture like sandpaper. Leaf stalks are often red-tinted. The stems are erect and weakly angled. The stems are often covered in many small purple spots.
Other Names:
Canada Cocklebur, Clotbur, Common Cocklebur, Common Cocklebur, Large Cocklebur, Woolgarie Bur.
Frequency (UK):

Other Information


Xanthium strumarium, also known as common cocklebur or rough cocklebur, is a species of flowering plant in the family Asteraceae. It is native to North and Central America, but it has been introduced to many other parts of the world and is now found on every continent except Antarctica. Common cocklebur is a tall, herbaceous plant that grows in a variety of habitats, including fields, roadsides, and waste areas. It has rough, hairy stems and leaves, and it produces small, yellow flowers that are followed by spiny, bur-like fruit. The plant is considered a weed in many parts of the world due to its ability to grow aggressively and displace native vegetation.


Rough Cocklebur: Understanding Xanthium strumarium

Xanthium strumarium, commonly known as rough cocklebur, is a weed species native to North America but now found globally in a variety of habitats. It's a biennial plant that can grow up to 2-6 feet tall and produces large, rough burrs that are easily spread by animals, wind, and water.

The plant is well adapted to disturbed areas and often grows in waste places, along roadsides, and in cultivated fields. It's also considered a noxious weed in many areas due to its aggressive growth habits and ability to outcompete native plant species.

Rough cocklebur is toxic to livestock and can cause health problems if ingested. The plant contains a toxic compound known as carboxyatractyloside, which can cause liver and kidney damage. It's also known to cause skin irritation and allergic reactions in some people.

Control of rough cocklebur is challenging and requires a combination of cultural, mechanical, and chemical methods. Cultural control methods include planting competitive crops and maintaining healthy soils, while mechanical control methods include hand-pulling and mowing. Chemical control methods include the use of herbicides, but it's important to carefully follow label instructions and take precautions to minimize non-target impacts.

Rough cocklebur is a noxious weed that can have negative impacts on both human and animal health, as well as the environment. Effective control requires a multi-faceted approach that includes cultural, mechanical, and chemical methods. By understanding the biology and ecology of this species, we can work to manage its spread and minimize its impact on our communities and ecosystems.

In addition to its negative impacts, rough cocklebur also has some cultural and historical significance. The plant has been used for medicinal purposes by indigenous people in North America and has also been used to make twine and other fibers.

Despite its aggressive growth habits and toxicity, rough cocklebur has also been found to have some potential benefits. For example, recent research has shown that extracts of the plant have antifungal and antibacterial properties, making it a potential candidate for the development of new medicines.

However, it's important to remember that while the plant has some potential benefits, its negative impacts far outweigh its positive aspects. Therefore, it's crucial that we continue to work towards managing and controlling its spread.

Overall, rough cocklebur is an interesting and complex species that has both negative and positive aspects. It's important that we continue to study and understand this plant so that we can effectively manage its impact on our communities and ecosystems.

Additionally, rough cocklebur is also an important food source for many wildlife species, such as birds and small mammals. The seeds and leaves of the plant provide valuable nutrition, particularly during the fall and winter months when other food sources may be scarce.

In some regions, rough cocklebur is also an important honey plant, providing nectar and pollen to honey bees and other pollinators. This highlights the interconnectedness of species in our ecosystems and the importance of considering both the positive and negative impacts of a species when managing its populations.

There are also efforts underway to use rough cocklebur for phytoremediation, or the use of plants to clean up contaminated soils and water. Research has shown that the plant is capable of removing heavy metals from contaminated soils, making it a potential tool for the cleanup of contaminated sites.

In conclusion, rough cocklebur is a complex and multifaceted species that has both positive and negative impacts on our communities and ecosystems. While it's important to continue to manage and control its spread, it's also important to consider the potential benefits and opportunities that the plant presents. By doing so, we can make the best use of our resources and minimize the negative impact of this aggressive weed.

Distribution Map

Reproduced by kind permission of the BSBI.

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